Abstract
This report deals with the effect of levels of concentrate supplementary feeding (Nil, 0.25% BW and 0.75% BW) on the productivity of different genotypes (Thai native (TN), 25% Anglo-Nubian (AN), 50% AN and 75% AN) of female goats grazing newly established pasture in a tropical area. The major species of grass was Brachiaria mutica (33%) and of legumes was Centrosema pubescens (34%). There was no significant (p>0.05) difference between nil and 0.25% BW supplementary feeding for growth rate ($g/kg^{0.75}/d$). However, goats fed 0.75% BW supplementary feeding had significantly (p<0.01) higher growth rates than did other treatments. There was no significant (p>0.05) difference among genotypes and between age for growth rate. There was no interaction between feeding and genotype for growth rate.